Particle Size of course depends on the scale we are interested in. Still at a particular scale what will be the relative size?
It seems in certain estimates that the electron is larger than the proton!
p charge radius=0.8751(61)fm,
p magnetic radius=0.776(34)(17)fm,
electron is a point-particle,its radius
Scattering experiments have historically suggested that the electron is much smaller than a proton. In very high speed protons the apparent size may be smaller than slow electrons.
@Huang, thank you for the information about proton size.
What about electron size estimates?
@Pradhan :You can query this reference: Dehmelt. A Single Atomic Particle Forever Floating at Rest in Free Space: New Value for Electron Radius. Phys. Scr. 1988 102
Well,I think it is very important to exchange knowledge with each other. I hope you could benefit from it。
Interestingly the electron is taken to be the typical point particle without any internal structure in all.physics text books notwithstanding the fact of its larger size compared to neutron and proton.
In general it seems that look at the size of the things depends on the energy scale we use to probe it. Meanwhile, for massive particles, we may think its mass-energy value as a convenient energy scale to measure its size.
In the case of the proton of mass M, the MIT bag model furnishes for its radius (please see [1,2,3]) the relation
Rp = 4 ħ c ∕ (M c2). (1)
Putting numbers in relation (1), we get
Rp ≈ 0.84 x 10 -15 m. (2)
With respect to the electron of mass me, the “classical” radius of it is given by the equation
me c2 = α ħ c ∕ Re. (3)
This leads to
Re ≈ 2.8 x 10 -15 m. (4)
However, we may consider the weak radius of the electron as follows. We have the energy(E) dependent weak coupling defined as
αw(E) ≈ (α ∕ 2) (E ∕ Mw) 2. (5)
In (5), Mw is the mass-energy of the W-boson of approximately 80.4 GeV. Now we write
me c2 = αw(me c2) ħ c ∕ Rw. (6)
Relation (6) implies
Rw = α ħ c me ∕ (Mw c) 2. (7)
Putting numbers in (7), we obtain
Rw ≈ 6 x 10 -26 m. (8)
[1] Xiangdong Ji, Origins of the Mass of BaryonicMatter, terpconnect.umd.edu/~xji/mass.ppt
[2] R. L. Jaffe, Nature 268, 201 (1977).
[3] A. Chodos, R. L. Jaffe, C. B. Thorn and V. F. Weisskopf, Phys. Rev. D 9, 3471 (1974).
Thanks Preston.
I will see your works.
Just note how in all diagrams and illuastations the electron is shown as a small point compared to the proton or even the nucleus!
This error of scientific imagination must be eradicated soon.
Regards.
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